相关论文: A cosmological model with complex scalar field

If the inflaton is a heavy scalar field, it may equilibrate slower than some other degrees of freedom, e.g. non-Abelian gauge bosons. In this case, perturbations in the inflaton field and in a thermal plasma coexist from a given moment…

We study two-field inflation derived from a single complex scalar field with a nonzero vacuum expectation value. The dynamics of inflation are governed by two parameters, the vacuum expectation value and the mass parameter of the phase…

A scale-invariant universe can have a period of accelerated expansion at early times: inflation. We use a frame-invariant approach to calculate inflationary observables in a scale invariant theory of gravity involving two scalar fields -…

We construct a model of quintessential inflation in Palatini $R^2$ gravity employing a scalar field with a simple exponential potential and coupled to gravity with a running non-minimal coupling. At early times, the field acts as the…

We explore a cosmological model in which the time scale is variable with the expansion of the universe and the effective spacetime is driven by the inflaton field. An example is considered and their predictions are contrasted between Planck…

The Universe is currently in a phase of accelerated expansion, a fact that was experimentally proven in the late 1990s. Cosmological models involving scalar fields allow the description of this accelerated expansion regime in the Cosmos and…

We present a model where early inflation and late accelerating expansion of the Universe are driven by the real and imaginary parts of a single complex scalar field, which we identified as inflaton and phantom field, respectively. This…

A new idea of deriving a cosmological term from an underlying theory has been proposed in order to explain the expansion history of the universe. We obtain the scale factor with this derived cosmological term and demonstrate that it…

The scalar field theory of cosmological inflation constitutes nowadays one of the preferred scenarios for the physics of the early universe. In this paper we aim at studying the inflationary universe making use of a numerical lattice…

The present paradigm in cosmology is the usual Big-Bang Cosmology in which two stages of accelerated expansion are incorporated: the inflationary phase in the very early universe which produces the classical inhomogeneities observed in the…

We explore within the context of brane cosmology whether it is possible to obtain both early inflation and accelerated expansion during the present epoch through the dynamics of the same scalar field in an exponential potential.…

Recently, attempts have been made to understand the apparent near coincidence of the present dark energy and matter energy in terms of a dynamical attractor-like solution for the evolution of a scalar field. In these models the field…

We study the dynamics of a scalar inflaton field with a symmetric double--well potential and prove rigorously the existence of a limit cycle in its phase space. By using analytical and numerical arguments we show that the limit cycle is…

We study the possibility to construct an observationally viable scenario where both early Inflation and the recently detected accelerated expansion of the universe can be explained by using a single scalar field associated with the Tachyon.…

The inflationary phase of the Universe is explored by proposing a toy model related to the scalar field, termed as {\it inflaton}. The potential part of the energy density in the said era is assumed to have a constant vacuum energy density…

We study the most general cosmological model with real scalar field which is minimally coupled to gravity. Our calculations are based on Friedmann-Lemaitre-Robertson-Walker (FLRW) background metric. Field equations consist of three…

The evolution of a scalar field is explored taking into account the presence of a background fluid in a positively curved Universe in the framework of loop quantum cosmology. Though the mechanism that provides the initial conditions for…

Inflation is considered to be the best paradigm for describing the early universe. However, it is still unclear what is the nature of the field which drives inflation. In this talk, we discuss the possibility of spinor field driving…

We investigate the cosmological perturbation of two-scalar field model during the reheating phase after inflation. Using the exact solution of the perturbation in long-wavelength limit, which is expressed in terms of the background…

An exact scalar field cosmological model is constructed from the exact solution of the field equations. The solutions are exact and no approximation like slow roll is used. The model gives inflation, solves horizon and flatness problems.…